612 
NATURE i 
[OcToBER 19, 1899 
iodide, and the effect of different amounts of iodide at different 
dilutions. —Mineralogical structure and chemical composition of 
the Trap of Rocky Hill, N.J., by A. FH. Phillips. The Rocky 
Hill trap, from its holocrystalline nature, would be classed as a 
dolerite. From the character of the decomposition of the 
olivine, and the solution cavities in the diallage crystals, the 
intrusive nature of this dike is evident, as it must have been 
formed at a considerable depth below the surface and under 
very heavy pressure.—Some analyses of Italian volcanic rocks, 
by H. S. Washington. This paper deals with the composition 
of trachytes of the Phlegrean Fields and of Ischia. There are 
three parallel volcanic lines in the Italian district. The latest, 
along the peninsula, is characterised chiefly by high K,O, by 
high CaO, and the presence of leucite. The next, that of the 
islands along the west coast, is high in alkalis, but with Na,O 
rather higher than K,O, and without leucite. The third, which 
lies far out in the Mediterranean, and which is possibly the 
oldest, is much higher in soda, and seems to be characterised by 
the presence of peculiar soda minerals such as enigmatite and 
eginine, nepheline also occurring in places. —Thermo-electricity 
in certain metals, by L. Holborn and A. L. Day. This is an 
English version of the author’s Reichsanstalt paper on the gas 
thermometer. 
SOCIETIES AND ACADEMIES. 
Paris. 
Academy of Sciences, October 9.—M. van Tieghem in 
the chair.—On the elastic equilibrium of a rectangular plate, 
by M. Maurice Lévy.—Some remarks on double integrals of 
the second species in the theory of algebraic surfaces, by M. 
Emile Picard. —On a modification of Bessel’s method for calcu- 
lating occultations, by M. L. Cruls. In the modification sug- 
gested use is made of the time of apparent conjunction of the 
two stars. The advantage resulting from this method is two- 
fold: it gives by a single calculation a precision generally only 
obtainable by a second approximation, and lends itself easily to 
a graphical construction and a simple geometrical interpretation 
of the different elements upon which the conditions of the 
phenomenon depend.—Observations of the Giacobini Comet 
(1889 e) made at the Observatory of Besancon, by M. P. 
Chofardet. The observations were made on the nights of 
October 3 and 4. The comet had the appearance of a nebulous 
‘sphere, 1’ in diameter, and having a slight nucleus of about the 
13th magnitude.—On fundamental functions and on the de- 
velopment of a holomorphic function at the interior of a contour 
in a series of fundamental functions, by M. Renaux.—On the 
stereochemistry of nitrogen, by M. J. A. Le Bel. The author 
replies to various criticisms by van’t Hoff, Markwald and others 
on his work published in 1891 on the preparation of active com- 
pounds from methyl- ethyl- propyl-isobutylammonium chloride, 
and lays down the exact experimental conditions necessary to 
repeat his results. The conclusion is drawn that there can 
now be no doubt as to the optical isomerism existing in 
the derivatives of ammonium chloride containing four different 
radicles, and containing at least ten atoms of carbon. It is also 
established that with derivatives less rich in carbon the stability 
of these optical isomerides is diminished.—On the reversible 
liquefaction of albuminoids, by M. Tsvett. It is known that 
the solution of albuminoids is favoured by certain acids, 
alkalis, and salts. The author has found that certain organic 
substances, such as resorcinol, pyrocatechol, phenol, chloral 
hydrate, &c., possess this liquefying property to a very marked 
extent. Thus a solution of gelatine treated with an eighty 
per cent. aqueous solution of resorcinol, forms two liquid 
layers, the upper a solution of gelatine in aqueous resorcinol, 
the lower a solution of aqueous resorcinol in gelatine, the co- 
efficients of reciprocal solubility varying with the concentra- 
tion of the resorcinol and the temperature. The phenomenon 
appears to be truly reversible.—On the volumetric estimation 
of quinones derived from benzene, by M. Amand Valeur. 
The quinones are reduced by a mixture of potassium 
iodide and hydrochloric acid, and the liberated iodine titrated 
with sodium thiosulphate. Experiments were carried out with 
quinone, dichloroquinone, toluquinone, and thymoquinone ; the 
results are quite satisfactory, and are very rapidly obtained,— 
On the structure of the nucleus in the myelocytes of Gasteropods 
and Annelids, by M. Joannes Chatin. The myelocytes of these 
invertebrates, contrary to the usual statements, may show a very 
NO. 1564, VOL. 60] 
clear, nuclear membrane.—On the alternation of generations in 
Cutlerta, by M. C. Sauvageau.x—On a gutta-percha plant 
capable of being cultivated in a temperate climate, by MM. 
Dybowski and G. Fron. The authors have extracted gutta- 
percha from the fresh leaves of Hucomza ulmoides. This plant 
can be grown in temperate climates, and ~ experiments were 
carried out as to the best mode of multiplication of the plant. 
It is easy to obtain good seeds in large quantity, but their ger- 
mination is difficult and capricious. Propagation through 
cuttings, however, offers no difficulties, the slips taking root 
easily and developing vigorously.—Action of anzesthetic vapours 
upon the vitality of dry and moist seeds, by M. Henri Coupin. 
The vitality of dry seeds is unaffected even by saturated ether 
and chloroform vapours ; but with moist seeds the case is quite 
different, the presence of only 377 c.c. of ether in 10 litres of 
air being sufficient to kill the seed. 
DIARY OF SOCIETIES. 
THURSDAY, Ocroser 19. 
Camera C ius, at 8.15.—Clouds and Photographic Landscapes: J. 
Cadett. 
TUESDAY, OctToBeER 24. 
Royal PHOTOGRAPHIC SOCIETY, at 8.—Wellington Film: Harry Wade 
FRIDAY, OctoBeER 27 
PuysicaL SOCIETY, at 5.—The Magnetic Properties of the Alloys of Iron 
and Aluminium: Dr. S. W. Richardson.—Exhibition of a Model illus- 
trating a Number of the Actions in the Flow of an Electric Current : 
G. L. Addenbrooke.— Repetition of some Experiments with the Wehnelt 
Interrupter devised by Prof. Lecher: W. Watson 
INSTITUTION OF MECHANICAL ENGINEERS, at 7.30.—The Incrustation 
of Pipes at Torquay Water Works: William Ingham.—A Continuous 
Mean-Pressure Indicator for Steam Engines: Prof. William Ripper. 
CONTENTS. PAGE 
Electro-magnetic Theory. By C.S. Whitehead . 589 
Our Book Shelf :— 
Robson: ‘* Catalogue of the Lepidoptera of North- 
umberland, Durham, and Newcastle-upon-Tyne. °— 
1 Oe | a cio) SEO 
“© The Process Year-Book for 1899”. . .« : coe Boe 
Wrapson and Gee: ‘‘ Mathematical Tables” . 590 
Maupin : ‘‘ Opinions et Curiosités touchant la Mathe- 
matique ” SIGS 590 
Letters to the Editor :-— 
Peripatus in the Malay Peninsula.—Prof. Edward 
BB: Poulton RiSteaememeise sy! * 591 
Dark Lightning Flashes.— Shelford Bidwell, 
F.R.S. . cg lee <0) : 3 . 591 
Heredity and Variation. —Prof. J. Mark Baldwin 591 
Phosphorescent Earthworms.—Prof. W. Blaxland 
Benham) 20. - eens. = Ge . 591 
Meeting of the International Meteorological Com- 
mittee) . ... <) ai-05) Sameer . 2) ES OFT 
The Coming Shower of Leonids. (Wzth Diagram.) 
By W. F. Denning . 592 
Notes MEPL MG Go % < 594 
Our Astronomical Column :— 
Comet Giacobinil(t899\e) Meee ;| - a 597 
Holmes’ Comet (1899d@) .... 597 
Opposition of Jupiter, 1899 ........ 597 
Law Connecting Motions in Planetary System 597 
On the Characteristics of a University. By Prof 
Rucker, F.R.S. 5): 10 Ree « 598 
Forthcoming Books of Science 601 
The British Association :— 
Section K.—Botany.—Opening Address by Sir 
George King, K.C.I.E., F.R.S., President of 
the’Section.. I) 2yageeens b 24 604! 
Chemistry at the British Association 608 
Geology at the British Association 610 
University and Educational Intelligence POLE 
Scientific Serial ... ee Ol 
Societies and Academies . 612 
Dianyol societies 2 meee 612 
